Acetoacetyl Thermosetting Resin for Zero VOC Gel Coat

ABSTRACT

Zero VOC thermosetting gel coat and laminating resin compositions, and composites and articles, are produced using a multifunctional Michael acceptor, a multifunctional Michael donor and a base catalyst. The obtained low viscosity resin is useful for producing zero VOC gel coats and laminates having excellent curability at ambient temperatures.

FIELD OF THE INVENTION

Embodiments of the invention relate generally to the field of gel coatsand laminating resins, and more particularly to methods of making lowviscosity, low to zero VOC acetoacetyl thermosetting resins for gel coatand laminating resin compositions utilizing a Michael-type additioncrosslinking reaction.

BACKGROUND OF THE INVENTION

The application of gel coats are widely used in numerous applications asthe external surface layer of composite molded articles. Gel coats aretypically found on composite articles that are exposed to theenvironment requiring moisture resistance, resistance to cracking andsimilar properties, or articles that require a strong, flexible,abrasion and impact resistant surface and/or a smooth glossy finish.Examples of such articles include boat hulls, bath tub enclosures,pools, spas, and body panels on cars and trucks, among others.

Such gel coated articles are typically formed by spraying a gel coatcomposition from a high pressure spray gun onto the inside surface of anopen mold, applying the materials and a laminating resin for thecomposite article onto the gel coat, curing the gel coat and thenremoving the cured gel coated article from the mold. Gel coated articlescan also be fabricated by applying the composite materials into amulti-part mold, injecting or applying the gel coat composition, closingthe mold, curing the gel coat and then removing the cured gel coatedarticle from the mold.

Gel coats for composite articles are typically formulated from athermosetting base resin system such as unsaturated polyester, acrylateand urethane type resins with incorporated fillers, pigments and otheradditives. The gel coat should exhibit low viscosity at high shear toallow for ease of application to the mold, but also resist sagging orrunning after it is applied. Another important property of gel coats issurface tackiness and cure time. A gel coat desirably produces a geltime of 10 to 20 minutes. Many low or zero VOC gel coats remain tackyafter several hours of curing.

Typically, the gel coat resin is mixed with reactive, polymerizablemonomers such as styrene or methyl methacrylate (MMA), which are alsoused to reduce resin system viscosity in order to apply the gel coat byspraying. Conventional gel coat compositions contain 35 to 45 wt % ofreactive monomers and other volatile organic compounds (VOCs). Thepresence of high amounts of styrene and other VOCs results the emissionof styrene vapors and other hazardous air pollutants (HAP), which areclosely regulated by government regulations. Consequently, thecomposites industry is very interested in providing gel coats that emitlow to zero VOCs.

However, there are difficulties in attaining gel coats having low tozero VOCs and acceptable application and performance properties. Severalapproaches have been described for addressing these requirements. Oneway to reduce VOCs is to reduce the molecular weight of the resin, whichleads to a lower viscosity and lower styrene need. However, inapplication, a gel coat made with a lower molecular weight resin tendsto remain tacky for long periods of time. The use of higher molecularweight resins results in higher viscosities that hamper sprayapplications of the gel coat composition, which generally require aviscosity in the range of 50 to 1200 cps under high shear. In order toachieve target viscosity, monomers with high boiling point are used toreplace monomers which contribute to VOC. These high boiling pointmonomers typically have higher viscosity and lower reactivity with aresin solid. As a result, a higher amount of high-boiling point monomersis required to replace the standard monomers in gel coat formulationsand the resulting product is very slow to cure.

There remains a significant need for a resin material that provides goodrheology properties for in-mold coating applications, fast curing and abetter cured gel coat product having low to zero VOCs and a high degreeof crosslinking.

SUMMARY OF THE INVENTION

The invention provides methods and gel coat and laminating resincompositions that overcome the above-described deficiencies and providestyrene free and zero VOC gel coats having a desirable viscosity forapplication, a fast gel time and set-up, and produce cured gel coats andlaminating resins having a high degree of crosslinking with excellentperformance properties.

In embodiments, the invention provides methods for making styrene freeand zero VOC gel coats. In one embodiment, the method comprises:

-   -   reacting a polyhydroxy polyol having at least two, preferably        three, hydroxyl groups per molecule with a C₁-C₅ alkyl        acetoacetate in a transesterification process to form a        crosslinkable, multifunctional acetoacetylated polyhydroxy        polyol having at least two acetoacetyl functional groups per        oligomer; and    -   combining the acetoacetylated polyhydroxy polyol with one or        more multifunctional acrylate monomers or oligomers, at least        one additive component, and a base catalyst, to form a        crosslinkable, thermosetting gel coat composition having a        viscosity of about 50 to 1200 cps under high shear.

In use, the gel coat composition can be used in making a gel coatedarticle. In embodiments, the gel coated article is fabricated by:

-   -   applying the thermosetting gel coat composition as an in-mold        coating to a surface of a mold;    -   allowing the gel coat composition to cure at ambient temperature        to form a partially crosslinked, tacky to tacky-free gel coat;    -   applying a material to be molded onto the partially crosslinked        gel coat;    -   applying a crosslinkable laminating resin onto said material,        the laminating resin comprising an acetoacetylated polyhydroxy        polyol having at least two, preferably three, acetoacetyl        functional groups per oligomer, one or more multifunctional        acrylate monomers or oligomers and a base catalyst; and    -   allowing the laminating resin and the gel coat to cure at        ambient temperature to a solid, crosslinked, thermoset resin        being styrene free with zero VOCs.

The resulting gel coated article comprises the cured thermoset gel coatbonded onto the surface of the article. In embodiments, the curedthermoset gel coat and laminating resin comprise crosslinkedacetoacetate functionalized acrylate oligomers, and are preferably atleast 50%, preferably 70 to 100%, crosslinked.

The invention also provides methods for making a laminating resincomposition. In embodiments, the method comprises:

-   -   reacting a polyhydroxy polyol having at least two, preferably        three, hydroxyl groups per molecule with a C₁-C₅ alkyl        acetoacetate in a transesterification process to form a        crosslinkable, multifunctional acetoacetylated polyhydroxy        polyol having at least two, preferably three, acetoacetyl        functional groups per oligomer; and    -   combining the acetoacetylated polyhydroxy polyol with one or        more multifunctional acrylate monomers or oligomers and a base        catalyst to form a crosslinkable, thermosetting laminating resin        composition having a Brookfield viscosity of about 50 to 1200        cps.

The laminating resin composition can be cured at ambient temperature toform a solid, crosslinked, thermoset resin comprising crosslinkedacetoacetate-functionalized acrylate oligomers, with the laminatingresin being styrene free with zero VOCs and preferably at least 50%,preferably 70 to 100%, crosslinked.

The invention further provides a crosslinkable, styrene free and zeroVOC gel coat composition. In an embodiment, the crosslinkable gel coatcomposition comprises an acetoacetylated polyhydroxy polyol, one or moremultifunctional acrylate monomers or oligomers, a base catalyst, and atleast one additive component selected from the group consisting offillers, pigments and thixotropic agents, and has a viscosity of about50 to 1200 cps under high shear, and is curable under ambient conditionsto form a solid thermoset gel coat comprising crosslinkedacetoacetate-functionalized acrylate oligomers, the gel coat beingstyrene free with zero VOCs and preferably at least 50%, preferably 70to 100%, crosslinked.

The invention also provides a crosslinkable, styrene free and zero VOClaminating resin composition. In an embodiment, the crosslinkablelaminating resin composition comprises an acetoacetylated polyhydroxypolyol, one or more multifunctional acrylate monomers or oligomers, anda base catalyst, and has a Brookfield viscosity of about 50 to 1200 cps,and is curable under ambient conditions to form a laminating resincomprising crosslinked acetoacetate-functionalized acrylate oligomers,the laminating resin being styrene free with zero VOCs and preferably atleast 50%, preferably 70 to 100%, crosslinked.

Also provided is a system for forming a gel coat composition. In anembodiment, the system is composed of separate containers packagedtogether, including:

-   -   a container of a curable, thermosetting gel coat composition        comprising a crosslinkable, multifunctional acetoacetylated        polyhydroxy polyol having at least two, preferably three,        acetoacetyl functional groups per oligomer, one or more        multifunctional acrylate monomers or oligomers and at least one        additive component selected from the group consisting of        fillers, pigments and thixotropic agents for a gel coat;    -   a container of a base catalyst selected from the group        consisting of 1,8-diazabicyclo-[5.4.0]undec-7-ene (DBU),        1,5-diazabicyclo[4,3,0]non-5-ene (DBN),        1,5,7-triazabicyclo[4,4,0]dec-5-ene (TBD),        7-methyl-1,5,7-triazabicyclo[4,4,0]dec-5-ene (MTBD),        tetramethylguanidine (TMG) and 1,4-diazabicyclo[2.2.2]octane        (DABCO), and N′-butyl-N″,N″-dicyclohexylguanidine, and mixtures        thereof; and    -   directions for combining the contents of the containers to form        a thermosetting gel coat composition, which, in embodiments, has        a viscosity of about 50 to 1200 cps under high shear, is curable        at ambient temperature to form a crosslinked, styrene free and        zero VOC thermoset gel coat comprising crosslinked        acetoacetate-functionalized acrylate oligomers, which is        preferably at least 50%, preferably 70 to 100%, crosslinked.

A system is also provided for forming a laminating resin composition. Inan embodiment, the system is composed of separate containers packagedtogether, including:

-   -   a container of a curable, thermosetting laminating resin        composition comprising a crosslinkable, multifunctional        acetoacetylated polyhydroxy polyol having at least two,        preferably three, acetoacetyl functional groups per oligomer and        one or more multifunctional acrylate monomers or oligomers;    -   a container of a base catalyst selected from the group        consisting of 1,8-diazabicyclo-[5.4.0]undec-7-ene (DBU),        1,5-diazabicyclo[4,3,0]non-5-ene (DBN),        1,5,7-triazabicyclo[4,4,0]dec-5-ene (TBD),        7-methyl-1,5,7-triazabicyclo[4,4,0]dec-5-ene (MTBD),        tetramethylguanidine (TMG) and 1,4-diazabicyclo[2.2.2]octane        (DABCO), and N′-butyl-N″,N″-dicyclohexylguanidine, and mixtures        thereof; and    -   directions for combining the contents of the containers to form        a thermosetting laminating resin composition, which, in        embodiments, has a Brookfield viscosity of about 50 to 1200 cps,        is curable at ambient temperature to form a crosslinked, styrene        free and zero VOC thermoset laminating resin comprising        crosslinked acetoacetate-functionalized acrylate oligomers,        which is preferably at least 50%, preferably 70 to 100%,        crosslinked.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Embodiments of the invention relate to methods of making zero VOC,crosslinkable, thermosetting resins from acetoacetate-functionalizedpolyhydroxy polyols and multifunctional acrylate monomers or oligomersfor producing laminating resins and gel coat compositions, which arecrosslinked using a Michael-type addition reaction with a base catalystto obtain laminates and gel coated articles. The thermosetting resinshave excellent curability at ambient or room temperatures. Inembodiments, the process results in an at least 50%, preferably 70 to100%, crosslinked thermoset polymer network that is VOC and styrene freewith excellent mechanical properties.

The thermosetting resins are crosslinked without styrene orfree-radicals, using a Michael-type addition reaction with a basecatalyst at ambient temperatures to incorporate acrylate functionalityinto a multifunctional acetoacetylated polyhydroxy polyol to produce athermoset, crosslinked polymer network in which theacetoacetate-functionalized acrylate oligomers are up to 100%crosslinked.

Unless otherwise specified herein, the term “viscosity” refers to theviscosity of a polymer in monomer at 25° C. (77° C.) measured incentipoise (cps) using a Brookfield RV model viscometer. The viscosityunder high shear is measured by a cone and plate (CAP) viscometer at ashear rate of 10,000 l/s. The term “NVM” refers to non-volatile materialdispersed in a volatile substance (e.g., monomer) as measured accordingto ASTM D1259.

Unless stated otherwise, all percent and ratios of amounts are byweight.

Acetoacetate-Functionalized Polyhydroxy Polyol

The acetoacetate-functionalized polyhydroxy polyol has at least two, andin some embodiments preferably at least three acetoacetyl functionalgroups per oligomer. The functionalized polyol is then blended with amultifunctional acrylate to form a thermosetting, crosslinkable resin.

In embodiments of the invention, multifunctional acetoacetylated polyolscan be prepared by reaction of a polyhydroxy polyol (also termed“polyhydric alcohol” or “polymeric polyol”), in a transesterificationreaction with an alkyl acetoacetate compound, preferably a C₁-C₅ alkylacetoacetate.

Suitable polyhydroxy polyol compounds have an average of at least two,preferably at least three (i.e., tripolyol), hydroxyl groups permolecule. Non-limiting examples of polyhydroxy polyols include methylpropanediol (MPD), trimethylolpropane (TMP), trimethylpentanediol,di-trimethylolpropane (di-TMP), butyl ethyl propanediol (BEPD),neopentyl glycol (NEO), pentaerythritol (Penta), di-pentaerythritol(di-Penta), tris-2-hydroxyethyl isocyanurate (THEIC),4,4′-isopropylidenedicyclohexanol (hydrogenated bisphenol-A (HBPA),hydroxyl-functionalized acrylic polymers, among others, and mixtures oftwo or more of such compounds. In embodiments, the polyhydroxy polyolhas a hydroxyl number of from 30 up to 1850 mg/KOH/g, and a numberaverage molecular weight of 90 up to 5000 g/mol.

Non-limiting examples of suitable C₁-C₅ alkyl acetoacetates (esters ofacetoacetic acid) include methyl acetoacetate (MAA), ethyl acetoacetate(EAA), n-propyl acetoacetate, isopropyl acetoacetate, n-butylacetoacetate, tert-butyl acetoacetate (TBAA), pentyl (amyl)acetoacetate, n-pentyl acetoacetate, isopentyl acetoacetate, tert-pentylacetoacetate, acetoacetate-functionalized acrylic polymer based onacetoacetoxyetheyl methacrylate, including copolymers with differentacrylic monomers, among others, and mixtures of two or more of suchcompounds.

Procedures for preparing crosslinkable, functionalized acetoacetylatedpolyols by reaction of a polyol with an alkyl acetoacetate compound in atransesterification reaction are generally known in the art. Inembodiments, the polyol and alkyl acetoacetate compounds are reacted ina transesterification reaction at a temperature of 90 to 200° C. for 3to 15 hours to form the functionalized polyol. In some embodiments, 10to 90 wt % polyol is combined with 90 to 10 wt % alkyl acetoacetate,based on the total weight of the mixture.

In embodiments, at least 70% of the hydroxyl groups of the polyhydroxypolyol are converted to acetoacetyl groups, and more preferably 80 to100% of the hydroxyl groups are converted. In embodiments, theacetoacetylated polyols have an acetoacetyl content within a range offrom 5 to 80 weight %, a hydroxyl number within a range of 0 to 60 mgKOH/g, and acid value of 0 to 5 mg KOH/g, and a number average molecularweight (Mn) within a range of 250 to 6000 g mole⁻¹, preferably 300 to5000 g mole⁻¹.

In embodiments, the acetoacetate-functionalized polyol can be preparedin a multi-stage reaction in which the polyhydroxy polyol is initiallyreacted by the condensation reaction with a dicarboxylic acid/anhydrideor polyacid with a glycol or polyol. Non-limiting examples of suitablecarboxylic acids include isophthalic acid, orthophthalic acid,terephtalic acid, succinic acid, adipic acid, maleic acid, fumaric acid,azelaic acid, 1,4-cyclohexane dicarboxylic acid, itaconic acid, sebacicacid, tetrahydrophthalic anhydride, trimelitic anhydride, among others,and mixtures of two or more of such compounds. In embodiments, thedicarboxylic acid and polyhydroxy polyol are reacted in a first stagereaction at 150 to 225° C. for about 5 to 20 hours, until an acid valueof less than 20 mg KOH/g, preferably less than 10 mg KOH/g, is reached.In embodiments, the molar ratio of acid functional groups to hydroxylfunctional groups is 0.2 to 0.8. In a second stage reaction, an alkylacetoacetate compound is mixed with the resulting polyester polyol andthe reaction proceeds for about 3 to 15 hours to form theacetoacetate-functionalized polyol. In embodiments, 25 to 90 wt % of thepolyester polyol is combined with 75 to 10 wt % alkyl acetoacetate,based on the total weight of the mixture.

In another embodiment, the acetoacetate-functionalized polyhydroxypolyol can be prepared in a multi-step reaction, in which a C₂ to C₁₃alkanolamine is reacted with a cyclic, 5-ring hydroxy-functionalcarbonate in a first step to form a polyurethane polyol intermediate. Inembodiments, the molar ratio of alkanolamine to the 5-ring carbonate isat or about close to 1 with slightly excess of carbonate. Non-limitingexamples of suitable alkanolamines (also referred to as “aminoalcohols”) include monoethanolamine (MEA), propanolamine, isopropanolamine, and 2-aminobutanol, among others, and mixtures of two or more ofsuch compounds. Non-limiting examples of suitable 5-ring carbonatesinclude glycerine carbonate (GC), ethylene carbonate, propylenecarbonate and butylene carbonate, among others, and mixtures of two ormore of such compounds.

In embodiments, the alkanolamine and 5-ring hydroxy-functional carbonateare reacted at 20 to 75° C. for about 5 to 8 hours. In a second stagereaction, the resulting polyurethane polyol is mixed with an alkylacetoacetate compound and reacted for about 3 to 15 hours to form thefunctionalized acetoacetylated polyol.

In another embodiment, the acetoacetate-functionalized polyhydroxypolyol can be prepared in a multi-step reaction, in which the polyol isformed through free radical copolymerization of vinyl monomers and atleast one vinyl monomer containing hydroxyl groups. The resulting polyolcontains at least two, preferably three, hydroxyl functional groups ineach polymer. Non-limiting examples of suitable vinyl monomerscontaining hydroxyl groups include hydroxyethyl acrylate, hydroxyethylmethacrylate, hydroxypropyl acrylate, and hydroxylpropyl methacrylate,among others, and mixtures of two or more of such compounds.Non-limiting examples of suitable vinyl monomers include aromaticcompounds such as styrene, alpha-methyl styrene, vinyl toluene, vinylphenol and the like, and unsaturated esters such as acrylic andmethacrylic ester, vinyl laurate and the like, among others, andmixtures thereof. In a second stage reaction, the resulting polyol ismixed with an alkyl acetoacetate compound and reacted for about 3 to 15hours to form the functionalized acetoacetylated polyol.

In another embodiment, the acetoacetate functionalized polyhydroxypolyol is made directly by free radical copolymerization of vinylmonomers and at least one vinyl monomer contains acetoacetate functionalgroup. The resulting copolymer contains at least two, preferably three,acetoacetate functional groups in each polymer. Non-limiting examples ofsuitable vinyl monomers containing acetoacetate functional group includeacetoacetoxyethyl methacrylate (AAEM), acetoacetoxyethyl acrylate(AAEA), acetoacetoxypropyl methacrylate, acetoacetoxypropyl acrylate,acetoacetoxybutyl methacrylate, and acetoacetoxybutyl acrylate, amongothers, and mixtures thereof.

The resulting acetoacetylate-functionalized polymer is a thermosetting,crosslinkable resin, having at least two, and in some embodiments atleast three, acetoacetyl functional groups per polymer, which can beused, for example, in the formulation of laminating resins and gel coatcompositions.

Gel Coats

Gel coats (also termed “gel coat compositions”) are compositions in acurable (e.g., pre-cured) state, composed of a blend of one or more ofthe acetoacetate-functionalized polyhydroxy polyol resin material withone or more multifunctional acrylate monomers and/or oligomers and oneor more additives. Gel coats are typically free of fibers. Inembodiments, the acetoacetate-functionalized polyol is combined with theone or more multifunctional acrylate monomers or oligomers. Preferably,the molar ratio of the acetoacetate functional group to acrylatefunctional group is 0.2 to 5.0, and preferably, a molar ratio of 0.3 to3.0. In embodiments, 15 to 70 wt % of the acetoacetate-functionalizedpolyol is combined with 15 to 70 wt % of one or more multifunctionalacrylate monomers or oligomers and 2 to 40 wt-% additives, based on thetotal weight of the mixture.

The gel coat composition can be prepared by high speed dispersion of thefiller, pigment and other additives into the resin mixture. Theviscosity of the gel coat composition (without catalyst) can range from8,000 to 25,000 cps, and preferably 10,000 to 20,000 cps when measuredby Brookfield viscometer at 4 rpm.

Multifunctional acrylate monomers. Non-limiting examples of suitablemultifunctional acrylate monomers include trimethylolpropane triacrylate(TMPTA), di-trimethylolpropane tetraacrylate, tris(2-hydroxyethyl)isocyanurate triacrylate, ethoxylated trimethylolpropanetriacrylate, polyethylene glycol diacrylate, neopentyl glycoldiacrylate, pentaerythritol tetraacrylate, 1,2-ethylene glycoldiacrylate, 1,6-hexanediol diacrylate, 1,12-dodecanol diacrylate,hexanediol diacrylate, tripropylene glycol diacrylate, dipropyleneglycol diacrylate, amine modified polyether acrylates, glycerolpropoxylate triacrylate, dipentaerythritol pentaacrylate,dipentaerythritol hexaacrylate, ethoxylated pentaerythritoltetraacrylate, and the like, as well as mixtures and combinationsthereof.

Additives. The gel coat composition includes one or more additivecomponents, for example, one or more fillers, pigments, and/or otheradditives such thixotropic agents, promoters, stabilizers, extenders,wetting agent, leveling agents, air release agents, as practiced in theart to adjust and enhance the molding properties (e.g., color effect,sprayability, sag resistance, mechanical property consistency, etc.).Gel coats are typically free of fibers.

Examples of fillers for gel coats include inorganic (mineral) fillers,such as clay, magnesium oxide, magnesium hydroxide, aluminum trihydrate(ATH), calcium carbonate, calcium silicate, mica, aluminum hydroxide,barium sulfate, talc, etc., and organic fillers. The amount of filler inthe gel coat composition can generally range from 5 up to 30 wt %, basedon the total weight of the gel coat composition. Suitable pigmentsinclude inorganic pigments, such as titanium dioxide. Thixotropic agentsinclude silica compounds such as fumed silica and precipitated silica,and inorganic clays such as bentonite clay, which, if included, can bepresent in an amount ranging from 0.3 up to 6 wt %, based on the totalweight of the gel coat composition.

Laminating Resin

In embodiments, the acetoacetate-functionalized polyhydroxy polyol resinmaterial can be combined with one or more multifunctional acrylatemonomers/oligomers (as described above) to form a curable laminatingresin composition. In embodiments, the laminating resin composition iscomposed of 10 to 90 wt % of the acetoacetate-functionalized polyolcombined with 90 to 10 wt % of multifunctional acrylatemonomers/oligomers, based on the total weight of the mixture.Preferably, the ratio of the functionalized polyol to multifunctionalacrylate monomer/oligomer is 0.2 to 8.5, and more preferably a ratio of0.25 to 8.0 (w/w). The viscosity of the laminating resin composition ispreferably about 50 to 1200 cps.

In use, the laminating resin composition is combined with a basecatalyst, and can be utilized in many applications such as for coatingsand in reinforced composite products by various open and closed moldingprocesses such as spray-up, hand lay-up, resin transfer molding and wetmolding.

Applications

In use, the gel coat composition is combined with a base catalyst andapplied as an in-mold coating, typically by manual application or usinga gel coat spray technique, onto the surface of a mold that is in theshape and form of the desired article (e.g., bathtub, car or aircraftpart, boat hull, swimming pool, etc.). The gel coat is allowed topartially cure such that it is tacky to tacky-free.

The amount of base catalyst included in the gel coat composition istypically 0.2 to 2.5% by weight, based on the total weight of thecomposition. For optimal processibility, gel time and cure time, theviscosity of the gel coat (with catalyst) can range from 8,000 to 25,000cps, and preferably 10,000 to 20,000 cps measured by Brookfieldviscometer at 4 rpm. Preferably, the gel time of the gel coat is 5 to 30minutes at ambient temperature. The term “gel time” refers to the timefrom catalyzation of the gel coat (or laminating resin) to cessation offlow.

Crosslinking of the laminating resin and gel coat occurs by abase-catalyzed Michael-type addition reaction of theacetoacetate-functionalized polyhydroxy polyol and multifunctionalacrylate monomers or oligomers at ambient temperatures (about 20 to 25°C.), without heat or UV radiation. The base catalysts are nitrogencontaining compounds, which can be represented by the general formulaR^(x)R^(y)R^(z)N, where R^(x), R^(y), and R^(z) each individually mayrepresent hydrogen, or a C₁-C₂₀ alkyl, aryl, alkylaryl or arylalkylgroup, that each optionally may contain one or more hetero-atoms (e.g.oxygen, phosphor, nitrogen or sulfur atoms) and/or substituents. Thegroup may be linear or branched; they also may contain one or moreunsaturations or substituents. This general formula R^(x)R^(y)R^(z)Nalso represents nitrogen compounds, wherein the nitrogen atom shown inthe formula is part of a cyclic system formed by two of the groupsR^(x), R^(y), and R^(z), or is present in the form of an imine group oras a phosphazene. Non-limiting examples of suitable base catalystsinclude 1,8-diazabicyclo-[5.4.0]undec-7-ene (DBU),1,5-diazabicyclo[4,3,0]non-5-ene (DBN),1,5,7-triazabicyclo[4,4,0]dec-5-ene (TBD),7-methyl-1,5,7-triazabicyclo[4,4,0]dec-5-ene (MTBD),tetramethylguanidine (TMG) and 1,4-diazabicyclo[2.2.2]octane (DABCO),and N′-butyl-N″,N″-dicyclohexylguanidine, and the like. In embodiments,the base catalyst can be combined with an organic solvent such asmethanol, ethanol, propanol, n-butyl alcohol, acetone, methyl ethylketone, among others, and mixtures thereof. In preferred embodiments,the base catalyst is used neat (absence of a solvent).

The article can be a fully or partially cured polymer resin or compositeof reinforcing material in a polymer resin matrix. In embodiments, areinforcing material for forming the article is laid into the open moldonto the partially cured gel coat material. Non-limiting examples ofreinforcing materials include glass fiber, polyethylene fiber, carbonfiber, metal fiber, ceramic fiber, or other material used in thecomposite plastics industry. In embodiments, dry fibers (e.g., glassfibers, glass fiber matt, etc.) are laid onto the partially cured gelcoat within the open mold.

The reinforcing material is then wet out by applying a laminating resinin a curable (i.e., pre-cured) state that has been combined with a basecatalyst. In embodiments, the laminating resin is composed of 10 to 90wt % of the acetoacetate-functionalized polyol, 90 to 10 wt % ofmultifunctional acrylate monomers or oligomers, and 0.2 to 2.5 wt % basecatalyst, based on the total weight of the mixture.

The laminating resin is allowed to cure to form a hardenedfiber-reinforced resin composite in the desired shape within the mold.The gel coat becomes an integral part of the finished laminate articleby forming a covalent interfacial bond with the laminating resin that isused. The gel coat provides a primary bond at the interface with thecomposite article, unlike the application of a resin coating onto theformed article.

Curing of the laminating resin can be conducted at ambient temperaturefor about 4 to 40 hours. The gel coated, composite article can then beremoved from the mold for use. In some embodiments, the laminate canundergo a post-cure, for example, by heating the mold to an elevatedtemperature (i.e., to 65° C.) to further increase the degree of cure.

The gel coats of the invention provide a durable and high weather- andwear-resistant coating with good hydrolytic stability, and/or anaesthetic finished surface to the article being produced to improvesurface appearance. The gel coats also provide a resilient, light-stablesurface covering and, in embodiments, are sufficiently pigmented toyield a desired color. The base catalyzed Michael addition ofacetoacetylated resins to acrylate acceptors produces crosslinkednetworks with low to no volatile organic compounds (VOCs). Inembodiments, the cured gel coat and/or laminating resin is at least 50%crosslinked, and preferably 70 to 100% crosslinked. Such crosslinkingcan be assessed, for example, by measuring the residual reactionexotherm by differential scanning calorimetry (DSC).

The invention will be further described by reference to the followingdetailed example. This example is not meant to limit the scope of theinvention that has been set forth in the foregoing description.Variation within the concepts of the invention is apparent to thoseskilled in the art. The disclosures of the cited references throughoutthe application are incorporated by reference herein.

EXAMPLES

The following examples are illustrations of the present invention. Theyare not to be taken as limiting the scope of the claimed invention.Unless stated otherwise, all percent and ratios of amounts are byweight.

Materials and Abbreviations.

The following materials were used in the Examples below.

Ingredient SR355 Di-trimethylolpropane tetraacrylate(Sartomer Co.) SR368Tris(2-hydroxy ethyl)isocyanurate triacrylate(Sartomer Co.) SR454Ethoxylated trimethylolpropane triacrylate(Sartomer Co.) TMPTATrimethylolpropane triacrylate DBU 1,8-Diazabicyclo-[5.4.0]undec-7-eneDABCO 1,4-Diazabicyclo[2.2.2]octane TMG Tetramethylguanidine

Example 1 Preparation of TMP Tris-Acetoacetate

A 3 liter, 4-neck round-bottom flask fitted with mechanical stirrer,pressure equalizing addition funnel (nitrogen inlet), thermocoupleconnected to a controller and heating mantle, was charged with 604 g(4.50 mol) trimethylolpropane (TMP), 850 g toluene and 303 g (1.92 mol)tert-butyl acetoacetate. The mixture was heated to about 110° C.Additional tert-butyl acetoacetate, 1881 g (11.89 mol), was graduallyadded into flask through additional funnel over about 5 hours. After alltert.-butyl acetoacetate was added, the mixture temperature wasincreased gradually to 135° C. and keep at this temperature for 2 hours.A vacuum (26″ Hg) was applied to remove unreacted liquid and a slightyellow liquid product of 1713 g was obtained.

The reaction is illustrated in Scheme 1 below.

Example 2 Preparation of THEIC Tris-Acetoacetate

A 2 liter, 4-neck round-bottom flask fitted with mechanical stirrer,pressure equalizing addition funnel (nitrogen inlet), thermocoupleconnected to a controller and heating mantle, was charged with 628 g(2.40 mol) tris(hydroxyl ethyl)isocyanurate (THEIC) and 1140 g (7.20mol) tert-butyl acetoacetate. The mixture was heated gradually to about150° C. in 5 hours and keep at this temperature for another 2 hours. Avacuum (26″ Hg) was applied to remove unreacted liquid and a yellowliquid product of 1214 g was obtained.

The reaction is illustrated in Scheme 2 below.

Example 3 Preparation of HBPA Di-Acetoacetate

A 1 liter, 4-neck round-bottom flask fitted with mechanical stirrer,pressure equalizing addition funnel (nitrogen inlet), thermocoupleconnected to a controller and heating mantle, was charged with 481 g(2.00 mol) 4,4′- isopropylidenedicyclohexanol (hydrogenated bisphenol-A(HBPA)) and 163 g (1.03 mol) tert-butyl acetoacetate. The mixture washeated to about 110° C. Additional tert-butyl acetoacetate, 502 g (3.17mol), was gradually added into flask through additional funnel overabout 3 hours. After all tert-butyl acetoacetate was added, thetemperature was increased gradually to 150° C. and keep at thistemperature for 2 hours. A vacuum (26″ Hg) was applied to removeunreacted liquid and a yellow liquid product of 865 g was obtained.

The reaction is illustrated in Scheme 3.

Example 4 Preparation of IPA-TMP Tetra-Acetoacetate

To a three-neck, round-bottom flask equipped with a mechanical stirrer,thermocouple connected to a controller and heating mantle, a Dean-Starktrap, a nitrogen inlet, and a water condenser, was charged 831 g (5.00mol) isophthalic acid (IPA) and 1342 g (10.00 mol) trimethylolpropane(TMP). The mixture was allowed to react at 215° C. for 8 hours until theacid number was determined to be less than 3.0 mg KOH/g equivalent.

To 1038 g of the above resulting polyester polyol, 1684 g tert-butylacetoacetate was gradually added over about 3 hours at 160-170° C. Afterall tert-butyl acetoacetate was added, the temperature was increasedgradually to 180° C. and kept at this temperature for another 2 hours. Avacuum (26″ Hg) was applied to remove unreacted liquid and a yellowliquid product of 1846 g was obtained.

The reaction is illustrated in scheme 4.

Example 5 Preparation of EA-GC Tris-Acetoacetate

To a three-neck, round-bottom flask equipped with a mechanical stirrer,thermocouple connected to a controller and heating mantle, a Dean-Starktrap, a nitrogen inlet, and a water condenser, was charged 184 g (3.00mol) ethanolamine (EA). 358 g (3.00 mol)4-hydroxymethyl-1,3-dioxolan-2-one (glycerine carbonate (GC)) was addedinto the flask over 0.5 hr at 20-40° C. The mixture was allowed to reactat 40-75° C. for 6 hours.

To the resulting urethane tripolyol, 1424 g tert-butyl acetoacetate wasadded and the temperature was increased gradually to 140° C. and kept atthis temperature for another 3 hours. A vacuum (26″ Hg) was applied toremove unreacted liquid and a dark yellow liquid product of 1239 g wasobtained.

The reaction is illustrated in Scheme 5.

Example 6 Preparation of Acetoacetate-Functionalized MethacrylateCopolymer Resin

To a three-neck, round-bottom flask equipped with a mechanical stirrer,thermocouple connected to a controller and heating mantle, a Dean-Starktrap, a nitrogen inlet, and a water condenser, was charged 500 g ofxylene. A monomer solution of 638 g (2.87 mol) isobornyl methacrylate,1052 g (4.91 mol) acetoacetoxyethyl methacrylate, 66 g dicumyl peroxideand 3 g 2-mercaptoethanol was added over 4 hr at 140° C. The mixture wasallowed to react at 140° C. for another 2 hr. A vacuum (26″ Hg) wasapplied to remove xylene and unreacted liquid. The obtained methacrylatecopolymer is solid at room temperature.

The reaction is illustrated in Scheme 6 below.

Example 7 Preparation of Gel Coat Composition

A gel coat composition was prepared by mixing, respectively, 252 g ofthe IPA-TMP Tetra-Acetoacetate from Example 4, 184 g of TMPTA, 120 g oftitanium dioxide, 30 g of talc and 4 g of fumed silica under high shear.The gel coat composition had a Brookfield viscosity of 20,000 centipoise(cps) at 25° C. (77° C.) at 4 rpm.

Example 8 Preparation of Laminating Resin Composition

A laminating resin was prepared by mixing, respectively, 263 g ofIPA-TMP Tetra (Acetoacetate) from Example 4 and 285 g of TMPTA. Thelaminating resin composition had a Brookfield viscosity of 900centipoise (cps) at 25° C. (77° C.).

Example 9 Preparation of DBU Catalyst Solution

A catalyst solution of DBU was prepared by dissolving 20 g DBU in 7 gethanol. The solution is a clear liquid.

Example 10 Preparation of DABCO Catalyst Solution

A catalyst solution of DABCO was prepared by dissolving 30 g DABCO in 20g ethanol. The solution is a clear liquid.

Example 11 Gel Coat Laminate Panel Preparation

200 g of the gel coat composition from Example 7 was mixed with 2.7 gDBU catalyst solution from Example 9 by hand. The gel coat compositionwas sprayed on a waxed and buffed flat tempered glass plate to athickness of 15-40 mils (1 mil=0.001 inch). After 20 minutes at roomtemperature (25° C.), the gel coat film was tacky free.

200 g of the laminating resin from Example 8 was mixed with 2.48 g (1.24wt-%) DBU catalyst solution from Example 9. A ⅛″ laminate was formed byapplying a 1.5 oz chop-strained mat and the laminating resin/DBUcatalyst mixture onto the gel coat film. The laminate was allowed tocure for 16-20 hours at ambient temperature (25° C.), then removed fromthe mold and cut into test parts.

Example 12 Gel Coat Formulation

Gel coat formulations were prepared by mixing, respectively, TMPTris(Acetoacetate) (150 g) prepared from Example 1, theacetoacetate-functionalized methacrylate copolymer resin (68 g) preparedfrom Example 6, TMPTA (184 g), heptadecafluorodecyl acrylate (9 g, ZonylTA-N from DuPont), titanium dioxide (120 g), talc (30 g) and fumedsilica (4 g). The gel coat composition had a Brookfield viscosity of16650 centipoise (cps) at 25° C. (77° C.) at 4 rpm.

Example 13 Gel Coat Laminate Panel Preparation

The gel coat composition (200 g) prepared from Example 7 was mixed withthe catalyst solution of DBU (1.0 g) and ethanol (0.3 g), and sprayed ona waxed and buffed flat tempered glass plate to a thickness of 15-40MILS (1 MIL-0.001 inch). After 20 min., the gel coat film was tacky freeand a barrier coat (ARMORGUARD from CCP) was sprayed onto the film to athickness of 23 MILS. A ⅛″ laminate is made using chopped fiberglass anda polyester resin (STYPOL LSPA-2200, 40% mat/60% resin). Methyl ethylketone peroxide (MEKP) co-initiator at 1.2 wt % is used to cure thepolyester resin. The laminate is allowed to cure for 16-20 hours at roomtemperature, then removed from the mold and cut into test parts.

Example 14 Gel Coat Laminate Panel Preparation

The gel coat composition (200 g) prepared from Example 7 was mixed withthe catalyst solution of DABCO (1.0 g) and ethanol (1.0 g), and sprayedon a waxed and buffed flat tempered glass plate to a thickness of 15-40MILS (1 MIL-0.001 inch). After 12 hr., the gel coat film was somewhattacky and a barrier coat (ARMORGUARD from CCP) was sprayed onto the filmto a thickness of 23 MILS. A ⅛″ laminate is made using choppedfiberglass and a polyester resin (STYPOL LSPA-2200, 40% mat/60% resin).Methyl ethyl ketone peroxide (MEKP) co-initiator at 1.2 wt % is used tocure the polyester resin. The laminate is allowed to cure for 16-20hours at room temperature and 5 hours at 100° C., then removed from themold and cut into test parts.

Examples 15 to 21 Preparation of Clear Castings

Clear castings were prepared by mixing the resin, acrylate, and catalystlisted in Table 1 (below) by hand and pouring the resin mixture into acavity between two glass plates with ⅛″ spacing. The resin was cured atambient temperature overnight and post-cured at 100° C. for 5 hours. Thecured resins were tested for physical properties according to ASTM D638,D648, and D790. The results are listed in Table 1.

TABLE 1 Physical properties of clear casting of resin Example 15 16 1718 19 20 21 Resin, weight (g) Ex 1, 100 Ex 1, 100 Ex 1, 55 Ex 2, 162 Ex4, 132 Ex 5, 165 Ex 1, 150 Ex 6, 68 Acrylate, weight (g) TMPTA, SR355,SR368, 48 TMPTA, TMPTA, TMPTA TMPTA 100 100 SR454, 76 124 143 g 113 184TMPTA, 55 Catalyst, weight (g) TMG, 0.7 DBU, 0.7 Ex 10, 3.6 Ex 9, 2.3 Ex9, 2.3 Ex 9, 2.4 Ex 9, 2.3 Viscosity (cp) 95 310 1000 1000 900 — 340Mechanical Properties Tensile Strength (psi) 7500 6680 10460 10760 65108720 8840 Tensile Modulus (ksi) 451 449 514 509 420 456 468 Elongation(%) 2.3 1.9 3.2 3.9 1.7 4.3 3.6 Flex Strength (psi) 13730 12610 1727018130 16700 8600 1510 Flex Modulus (ksi) 432 438 488 510 477 318 433 HDT(° C.) 62 48 70 77 86 34 69

The mechanical properties of the examples have comparable properties totypical unsaturated polyester resins.

The invention has been described by reference to detailed examples andmethodologies. These examples are not meant to limit the scope of theinvention. It should be understood that variations and modifications maybe made while remaining within the spirit and scope of the invention,and the invention is not to be construed as limited to the specificembodiments disclosed. The disclosures of references cited in theapplication are incorporated by reference herein.

What is claimed:
 1. A method of making a styrene free and zero VOC gelcoat composition, comprising: reacting a polyhydroxy polyol having atleast two hydroxyl groups per molecule with a C₁-C₅ alkyl acetoacetatein a transesterification process to form a crosslinkable,multifunctional acetoacetylated polyhydroxy polyol having at least twoacetoacetyl functional groups per oligomer; and combining theacetoacetylated polyhydroxy polyol with one or more multifunctionalacrylate monomers or oligomers, at least one additive component, and abase catalyst, to form a crosslinkable, styrene free, zero VOC,thermosetting gel coat composition having a viscosity of about 50 to1200 cps under high shear.
 2. The method of claim 1, wherein thepolyhydroxy polyol has at least three hydroxyl groups per molecule. 3.The method of claim 1, wherein the acetoacetylated polyhydroxy polyolhas at least three acetoacetyl functional groups per oligomer.
 4. Themethod of claim 1, wherein the acetoacetylated polyhydroxy polyol has:an acetoacetyl content of 5 to 80 weight %, a hydroxyl number of 0 to 60mg KOH/g, an acid value of 0 to 5 mg KOH/g, and a number averagemolecular weight (Mn) of 250 to 6000 g mole³¹ ¹.
 5. The method of claim1, wherein the molar ratio of the acetoacetate functional group ofacetoacetylated polyhydroxy polyol to the acrylate functional group ofone or more acrylate monomers or oligomers is 0.2 to 5.0.
 6. The methodof claim 5, wherein the molar ratio is 0.3 to 3.0.
 7. The method ofclaim 1, wherein the gel coat composition comprises: 15 to 70 wt % ofthe acetoacetylated polyhydroxy polyol, 15 to 70 wt % of the one or moremultifunctional acrylate monomers or oligomers, and 2 to 40 wt-%additives, based on the total weight of the composition.
 8. The methodof claim 1, further comprising allowing the gel coat composition to cureat ambient temperature to form a crosslinked, thermoset gel coatcomprising crosslinked acetoacetylate-functionalized acrylate oligomers.9. The method of claim 8, wherein the gel coat is at least 50%crosslinked.
 10. The method of claim 8, wherein the gel coat is 70 to100% crosslinked.
 11. The method of claim 1, wherein the polyhydroxypolyol is selected from the group consisting of methyl propanediol(MPD), trimethylolpropane (TMP), trimethylpentanediol,di-trimethylolpropane (di-TMP), butyl ethyl propanediol (BEPD),neopentyl glycol (NEO), pentaerythritol (Penta), di-pentaerythritol(di-Penta), tris-2-hydroxyethyl isocyanurate (THEIC),4,4′-isopropylidenedicyclohexanol (hydrogenated bisphenol-A (HBPA), andhydroxyl-functionalized acrylic polymers, and mixtures thereof.
 12. Themethod of claim 1, wherein the C₁-C₅ alkyl acetoacetate is selected fromthe group consisting of methyl acetoacetate (MAA), ethyl acetoacetate(EAA), n-propyl acetoacetate, isopropyl acetoacetate, n-butylacetoacetate, tert-butyl acetoacetate (TBAA), pentyl(amyl)acetoacetate,n-pentyl acetoacetate, isopentyl acetoacetate, tert-pentyl acetoacetate,and acetoacetate-functionalized acrylic polymer based onacetoacetoxyethyl methacrylate, and mixtures thereof.
 13. The method ofclaim 1, wherein the additive component is selected from the groupconsisting of fillers, pigments, thixotropic agents, promoters,inhibitors, stabilizers, extenders, air release agents, leveling agents,and combinations thereof.
 14. The method of claim 1, wherein theadditive component comprises a filler selected from the group consistingof clay, magnesium oxide, magnesium hydroxide, aluminum trihydrate(ATH), calcium carbonate, calcium silicate, mica, aluminum hydroxide,barium sulfate and talc, and mixtures thereof.
 15. The method of claim1, wherein the additive component comprises titanium dioxide.
 16. Themethod of claim 1, wherein the additive component comprises athixotropic agent selected from the group consisting of fumed silica,precipitated silica, and bentonite clay, and mixtures thereof.
 17. Themethod of claim 1, wherein the base catalyst is selected from the groupconsisting of 1,8-diazabicyclo-[5.4.0]undec-7-ene (DBU),1,5-diazabicyclo[4,3,0]non-5-ene (DBN),1,5,7-triazabicyclo[4,4,0]dec-5-ene (TBD),7-methyl-1,5,7-triazabicyclo[4,4,0]dec-5-ene (MTBD),tetramethylguanidine (TMG) and 1,4-diazabicyclo[2.2.2]octane (DABCO),and N′-butyl-N″,N″-dicyclohexylguanidine, and mixtures thereof.
 18. Amethod of making a gel coated article, comprising: reacting apolyhydroxy polyol having at least two hydroxyl groups per molecule witha C₁-C₅ alkyl acetoacetate in a transesterification process to form acrosslinkable, multifunctional acetoacetylated polyhydroxy polyol havingat least two acetoacetyl functional groups per oligomer; combining theacetoacetylated polyhydroxy polyol with one or more multifunctionalacrylate monomers or oligomers, at least one additive component, and abase catalyst, to form a crosslinkable thermosetting gel coatcomposition having a viscosity of about 50 to 1200 cps under high shear;and applying the thermosetting gel coat composition as an in-moldcoating to a surface of a mold; allowing the gel coat composition tocure at ambient temperature to form a partially crosslinked, tacky totacky-free gel coat; applying a material to be molded onto the partiallycrosslinked gel coat; applying a crosslinkable laminating resin ontosaid material, the laminating resin comprising an acetoacetylatedpolyhydroxy polyol having at least two acetoacetyl functional groups permolecule, one or more multifunctional acrylate monomers or oligomers anda base catalyst; and allowing the laminating resin and the gel coat tocure at ambient temperature to a solid, crosslinked, thermoset resinbeing styrene free with zero VOCs.
 19. The method of claim 18, whereinthe polyhydroxy polyol has at least three hydroxyl groups per molecule.20. A method of making a laminating resin composition, comprisingreacting a polyhydroxy polyol having at least two hydroxyl groups permolecule with a C₁-C₅ alkyl acetoacetate in a transesterificationprocess to form a crosslinkable, multifunctional acetoacetylatedpolyhydroxy polyol having at least two acetoacetyl functional groups peroligomer; and combining the acetoacetylated polyhydroxy polyol with oneor more multifunctional acrylate monomers or oligomers and a basecatalyst to form a crosslinkable thermosetting laminating resincomposition having a Brookfield viscosity of about 100 to500 cps. 21.The method of claim 20, wherein the multifunctional acetoacetylatedpolyhydroxy polyol has at least three acetoacetyl functional groups peroligomer.
 22. The method of claim 20, further comprising allowing thelaminating resin to cure at ambient temperature to form a styrene free,zero VOC, solid, crosslinked thermoset laminating resin comprisingcrosslinked acetoacetate-functionalized acrylate oligomers.
 23. Themethod of claim 22, wherein the thermoset laminating resin is at least50% crosslinked.
 24. A crosslinkable gel coat composition, comprising:an acetoacetylated polyhydroxy polyol, one or more multifunctionalacrylate monomers or oligomers, a base catalyst, and at least oneadditive component selected from the group consisting of fillers,pigments and thixotropic agents; the gel coat composition having aviscosity of 50 to 1200 cps under high shear, and curable under ambientconditions to a styrene free, zero VOC, solid thermoset gel coatcomprising crosslinked acetoacetate-functionalized acrylate oligomers.25. A crosslinkable laminating resin composition comprising: anacetoacetylated polyhydroxy polyol, one or more multifunctional acrylatemonomers or oligomers, and a base catalyst; the laminating resincomposition having a Brookfield viscosity of 50 to 1200 cps, and underambient conditions to a styrene free, zero VOC, solid thermosetlaminating resin comprising crosslinked acetoacetate-functionalizedacrylate oligomers.
 26. A gel coated article, comprising a curedthermoset gel coat on a surface of the article, the article comprising aresin, and said resin and the thermoset gel coat being crosslinked,solid and styrene free with zero VOCs, and comprising crosslinkedacetoacetate-functionalized acrylate oligomers.
 27. A system for forminga gel coat composition, comprising, in separate containers packagedtogether: a container of a curable, thermosetting gel coat compositioncomprising a crosslinkable, multifunctional acetoacetylated polyhydroxypolyol having at least two acetoacetyl functional groups per oligomer,one or more multifunctional acrylate monomers or oligomers and at leastone additive component selected from the group consisting of fillers,pigments and thixotropic agents for a gel coat, the thermosetting gelcoat composition having a viscosity of about 50 to 1200 cps under highshear and curable at ambient temperature to form a crosslinked,thermoset gel coat resin being styrene free with zero VOCs; a containerof a base catalyst selected from the group consisting of1,8-diazabicyclo-[5.4.0]undec-7-ene (DBU),1,5-diazabicyclo[4,3,0]non-5-ene (DBN),1,5,7-triazabicyclo[4,4,0]dec-5-ene (TBD),7-methyl-1,5,7-triazabicyclo[4,4,0]dec-5-ene (MTBD),tetramethylguanidine (TMG) and 1,4-diazabicyclo[2.2.2]octane (DABCO),and N′-butyl-N″,N″-dicyclohexylguanidine, and mixtures thereof; anddirections for combining the acetoacetylated polyhydroxy polyol and thebase catalyst to form a solid, crosslinked, styrene free, zero VOC gelcoat comprising crosslinked acetoacetate-functionalized acrylateoligomers.
 28. The system of claim 27, wherein the multifunctionalacetoacetylated polyhydroxy polyol has at least three acetoacetylfunctional groups per oligomer.
 29. A system for forming a laminatingresin composition, comprising, in separate containers packaged together:a container of a curable, thermosetting laminating resin compositioncomprising a crosslinkable, multifunctional acetoacetylated polyhydroxypolyol having at least two acetoacetyl functional groups per oligomerand one or more multifunctional acrylate monomers or oligomers; acontainer of a base catalyst selected from the group consisting of1,8-diazabicyclo-[5.4.0]undec-7-ene (DBU),1,5-diazabicyclo[4,3,0]non-5-ene (DBN),1,5,7-triazabicyclo[4,4,0]dec-5-ene (TBD),7-methyl-1,5,7-triazabicyclo[4,4,0]dec-5-ene (MTBD),tetramethylguanidine (TMG) and 1,4-diazabicyclo[2.2.2]octane (DABCO),and N′-butyl-N″,N″-dicyclohexylguanidine, and mixtures thereof; anddirections for combining the laminating resin and the base catalyst toform a solid, crosslinked, styrene free, zero VOC laminating resincomprising crosslinked acetoacetate-functionalized acrylate oligomers.30. The system of claim 29, wherein the multifunctional acetoacetylatedpolyhydroxy polyol has at least three acetoacetyl functional groups peroligomer.